ChemInform Abstract: Tunable, Chemoselective Amination via Silver Catalysis.

Rigoli, Jared W.; Weatherly, Cale D.; Alderson, Juliet M.; Vo, Brian T.; Schomaker, Jennifer M.

doi:10.1002/chin.201423042

Cited by 6 publications

(12 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They hypothesized that active intermediates in the catalytic cycle can be finely tuned by changing the ratio between metal and ligands. 398 When a bis-homoallyl carbamate was subjected to the AgOTf/1,10-phen (1:1.25) catalyst system, aziridination occurred predominantly. In contrast, an increase of the ligand to 3 equiv relative to the silver salt induced a reversal of the chemoselectivity, leading to C−H amination almost exclusively.…”

Section: C−h Insertion Catalysismentioning

confidence: 99%

Transition Metal-Catalyzed C–H Amination: Scope, Mechanism, and Applications

2017

View full text Add to dashboard Cite

Catalytic transformation of ubiquitous C-H bonds into valuable C-N bonds offers an efficient synthetic approach to construct N-functionalized molecules. Over the last few decades, transition metal catalysis has been repeatedly proven to be a powerful tool for the direct conversion of cheap hydrocarbons to synthetically versatile amino-containing compounds. This Review comprehensively highlights recent advances in intra- and intermolecular C-H amination reactions utilizing late transition metal-based catalysts. Initial discovery, mechanistic study, and additional applications were categorized on the basis of the mechanistic scaffolds and types of reactions. Reactivity and selectivity of novel systems are discussed in three sections, with each being defined by a proposed working mode.

show abstract

Section: C−h Insertion Catalysismentioning

confidence: 99%

Transition Metal-Catalyzed C–H Amination: Scope, Mechanism, and Applications

2017

View full text Add to dashboard Cite

show abstract

“…THE SILVER/LIGAND RATIO The ability of Ag(I) to accommodate diverse coordination geometries stimulated our curiosity as to whether changes in the Ag:ligand ratio could control chemoselectivity in nitrene transfer. 10,11 Table 1 compares the behavior of Rh 2 L n with Ag(I) complexes supported by 1,10-phenanthroline (phen) in reactions of homoallenic carbamates 1a−d to furnish bicyclic methyleneaziridines 2a−d and allenic amines 3a−d, respectively. 10 Rh 2 (esp) 2 (entries 1, 8, 11, and 14) yielded mixtures of 2:3, indicating significant substrate control; 2d,g however, a 1:1.25 AgOTf/phen stoichiometry with 1a−d (entries 4, 9, 12, and 15) gave good balance between yield and selectivity for 2a−d.…”

Section: Chemodivergent Amination Via Changes Inmentioning

confidence: 99%

“…In the course of the work described in this Account, four major design principles were identified for achieving chemo-, site-, and stereoselective nitrene transfer reactions (Figure 1) catalyzed by Ag(I) complexes supported by simple N-donor ligands: 9−19 (1) changing Ag/ligand ratios to influence chemoselectivity, [9][10][11]15,17,18 (2) manipulating the steric environment of the catalyst, [12][13][14]16 (3) promoting noncovalent interactions between Ag/substrate or substrate/ligand to direct C−H functionalization, 19 and (4) dictating the trajectory of approach of the substrate to the Ag-nitrene. 14,18 These general principles will be highlighted throughout the Account to inspire their applications to other metal-catalyzed C−H functionalizations.…”

Section: Introductionmentioning

confidence: 99%

Tunable, Chemo- and Site-Selective Nitrene Transfer Reactions through the Rational Design of Silver(I) Catalysts

2017

Self Cite

View full text Add to dashboard Cite

Carbon-nitrogen (C-N) bonds are ubiquitous in pharmaceuticals, agrochemicals, diverse bioactive natural products, and ligands for transition metal catalysts. An effective strategy for introducing a new C-N bond into a molecule is through transition metal-catalyzed nitrene transfer chemistry. In these reactions, a metal-supported nitrene can either add across a C═C bond to form an aziridine or insert into a C-H bond to furnish the corresponding amine. Typical catalysts for nitrene transfer include RhL and RuL complexes supported by bridging carboxylate and related ligands, as well as complexes based on Cu, Co, Ir, Fe, and Mn supported by porphyrins and related ligands. A limitation of metal-catalyzed nitrene transfer is the ability to predictably select which specific site will undergo amination in the presence of multiple reactive groups; thus, many reactions rely primarily on substrate control. Achieving true catalyst-control over nitrene transfer would open up exciting possibilities for flexible installation of new C-N bonds into hydrocarbons, natural product-inspired scaffolds, existing pharmaceuticals or biorenewable building blocks. Silver-catalyzed nitrene transfer enables flexible control over the position at which a new C-N bond is introduced. Ag(I) supported by simple N-donor ligands accommodates a diverse range of coordination geometries, from linear to tetrahedral to seesaw, enabling the electronic and steric parameters of the catalyst to be tuned independently. In addition, the ligand, Ag salt counteranion, Ag/ligand ratio and the solvent all influence the fluxional and dynamic behavior of Ag(I) complexes in solution. Understanding the interplay of these parameters to manipulate the behavior of Ag-nitrenes in a predictable manner is a key design feature of our work. In this Account, we describe successful applications of a variety of design principles to tunable, Ag-catalyzed aminations, including (1) changing Ag/ligand ratios to influence chemoselectivity, (2) manipulating the steric environment of the catalyst to achieve site-selective C-H bond amination, (3) promoting noncovalent interactions between Ag/substrate or substrate/ligand to direct C-H functionalization, and (4) dictating the substrate's trajectory of approach to the Ag-nitrene. Our catalysts distinguish between the aminations of various types of C-H bonds, including tertiary C(sp)-H, benzylic, allylic, and propargylic C-H bonds. Efforts in asymmetric nitrene transfer reactions catalyzed by Ag(I) complexes are also described.

show abstract

“…Our group has discovered the highly flexible coordination sphere of silver(I) presents new oppor-tunities for catalyst-controlled nitrene transfer. [31][32][33][34] In our hands, Ag(I) catalysis displays significant synthetic versatility, enabling tunable, chemoselective aziridination versus allylic C-H insertion in alkenes and allenes, 31,34 effective direct amination of propargylic C-H bonds in the presence of competing insertion sites, 32 and tunable, site-selective C-H amidation of competing C-H bonds. 33 The selective functionalization of C-H bonds using group transfer reactions remains of intense interest, owing to the ubiquity of these bonds in complex organic frameworks.…”

Section: Introductionmentioning

confidence: 99%